Electric motor.



E. M. FRASER.

ELECTRIC MOTOR.

APPLICATION FILED MAY 22, 1911. 1,094,71 1 Patented Apr. 28, 1914.

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E. M.- FRASER. ELECTRIC MOTOR.

APPLICATION FILED MAY 22, 1911.

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UNITED STATES PATENT OFFICE.

ETHELBERT M. FRASER, 0F YONKERS, NEW YORK.

ELECTRIC MOTOR.

To all whom it may concern.'

Be it known that I, ETHELBERT M. F RASEE, a citizen of the Dominion of Canada, residing at Yonkers, county of Westchester, and State of New York, have invented a new and useful Improvement in Electric Motors, of which the following is a specification.

My invention relates to an improved electric motor adapted for use with elevators, hoisting mechanism and all analogous mechanism operated by rope drive.

My invention is particularly adapted for use in connection with traction elevators, so-called, although it may be utilized in many and various ways for specific purposes,

vand can be adapted for those purposes by any one skilled in the art.

Heretofore in the case of traction type of elevators it has been customary to use the slow speed standard type of multipolar motors. Such motors, however, are very costly to build, are very heavy, and when placed at the top of a building, create extra strains which must be taken care of by heavier building construction. In suoli installations the elevator hoisting ropes pass over a rope sheave mounted on the motor shaft, and the slippage of the ropes on this sheave when starting and stopping the elevator causes excessive wear on the cables, as well as making the operation of the elevator very unsafe. To obviate this slippage to some extent an extra sheave has been used and several wraps of rope taken around this extra sheave and the main sheave. lVhile this arrangement increases the friction between the rope and the motor sheave, it also causes excessive wear on the cable due to the extra bending around the sheaves. Excessive strains are also put on the bearings of the motor by the multiplying action of the rope wrapped around the two sheaves, thereby causing extra friction and lowering the economy. Furthermore, when this type of motor is used the commutator must be necessarily large to keep down the voltage between the bars. Such a large commutator is expensive to build and maintain, and is more or less unsafe, as it cannot be made to hold its circular shape when subjected to the strain due to the expansion and contraction caused by heating. If the commutator is not perfectly round, the brushes will not Specification of Letters Patent.

Application filed May 22, 1911.

Patented Apr. 28, 1914.

Serial No. 628,770.

make good contact and suflicient current will not be conducted to the armature windings to properly control the movement of the elevator car.

One of the objects of my invention is to provide an electric motor, comprising a stationary armature, and a rotatable field structure that can be used as a pulley to operate a flexible driving connector.

Another object is to provide an electric motor, comprising a rotatable field and a stationary armature, wherein the field structure can be used as a pulley to operate a flexible driving connector of magnetic material, and in connection with the armature will exert a magnetic attraction upon said connector, thereby increasing the traction between the connector and the field.

Another object is to provide an electric motor, having a stationary armature and a rotatable field structure serving as a pulley to operate a flexible connector of magnetic material, in which the armature and field can be brought into closer magnetic relation, so as to lessen the load on the bearings of the field and to increase the magnetic attraction upon the connector by increasing the magnetic lines of force between the armature and field along that portion of the field engaged by the connector.

Another object is to provide electricallyoperated means for controlling the rotation of the field of the motor.

Another object is to provide means for automatically gripping the driving rope and stopping its movement upon failure of the current supply.

With the above and other objects in view, my invention consists of the construction, arrangements and combinations of parts hereinafter described and claimed.

A structure embodying the features of my invention is illustrated in the accompanying drawings forming a part of this specifica tion, in which-- Figure 1 is a side view of my improved motor. Fig. 9. is a side view of the lower part of the motor with a portion of the casing broken away. Fig. 3 is a section taken through the center of the machine at right angles to the axis of rotation on line -m of Fig. 4. Fig. 4 is a section taken through the center of the machine parallel to the axis of rotation taken on line g/-g/ of Fig. 3.

In the drawings, similar letters of reference refer to similar parts throughout the several views.

In general, my improved motor comprises a stator and a rotor, the latter of which can be used as a pulley to operate a flexible driving connector. In the preferred form, the rotor is the rotatable field, the stator being the stationary armature. The winding of the armature is preferably of the series system, in which the conductors connected to any two adjacent commutator segments must pass under all the poles of the machine, or else all the conductors in all the armature circuits pass under the same poles so that the counter-electromotive force generated in all the armature circuits will be exactly equal independent of any unequal distribution of magnetic lines.

Referring to the drawings, the numeral l indicates the main frame of the motor adapted to inclose the rotatable field structure 2 mounted upon the shaft 3 which is supported in the bearings t, mounted in the circular casings 5. The casings 5, which are smaller than the openings (il in the frame l, are secured to the frame by bolts 58, which pass through slots 59 in the casings 5, thereby permitting the casings to be adjusted in any direction at right angles to the axis of rotation of the field structure.

In the preferred form, my motor is of the multipolar type. As shown in the drawings, the field structure 2 comprises six poles, each pole having a pole-piece 6, the pole-pieces being connected together by suitable pieces 7 of non-magnetic material, so that the polepieces G and the non-magnetic pieces 7 will form a continuous ring. The rotatable field structure is thus adapted to be used as a pulley, in place of the pulley usually connected to the outer end of the motor shaft, to operate a flexible driving connector of magnetic material. In the preferred form of my invention said driving connector comprises a plurality of standard iron hoisting ropes 9, which pass over the peripheral face of the field structure and engage grooves S therein. Each of the poles of the field is suitably wound with a coil l0.

The field coils l0 are suitably connected to slip-rings 11 supported on a cylinder l2 of non-conducting material mounted upon one end of the motor shaft 3. In contact with the slip-rings l1 are the brushes 13 suitably secured to and insulated from the supporting bracket 14, which is secured to the frame l.

Mounted within the frame l is the stationary armature l5, surrounding the rotating fields and suitably spaced therefrom, the armature being provided at proper points with slots 1G to permit of the passage of the rope 9 therethough. rlhe armature winding being preferably of the series system, the ends of each series group of conductors are brought out and suitably connected to the bars of the stationary commutator 1S, which is secured to the frame l.

. `Means are' provided for adjusting the field structure in the direction of its diameter, so as to bring the lield into closer relation with the armature at any point. its shown, said means comprise the screws 60, which pass through the frame l and bear against the casings 5. By loosening the bolts 5S and adjusting the screws GO, a pre-determined portion of the field can be brought into closer relation with the armature. rlfhe effect of bringing a pre-determined portion of the field into closer relation with the armature is to lessen or magnetically reduce the air-gap therebetween, thus increasing the number of magnetic lines of force between the armature and field along that portion and creating a greater magnetic attraction between the field and armature. If the portion of the field structure thus brought into closer or eccentric relation with the armature is that part of the field structure over which the magnetic connector passes, the load on the bearings of the field structure will be lessened and the traction between the connector and field increased.

Upon the other end of the shaft 3 is a gear 19 which meshes with the gear Q0 mounted on the end of the shaft 2l, which passes up through the stationary commutator 1S. rthis shaft 2l carries near its upper end a rotatable brush yoke 22 which carries the brushes 23, preferably two in number, which are adapted to bear upon the commutator 18. On the upper end of the shaft 2l is a cylinder 2st of non-conducting material carrying slip-rings S25 connected to the movable brushes 23. In contact with the slip-rings Q5 are the brushes 2G, which are secured to and insulated from the supporting bracket Q7, secured to the frame l.

.as the armature winding is of the series type, there can only ne two ends to eacl group of conductors no matter how many pairs of poles are used in the rotating field. That being the case, only a suliicient number of bars need be used in the commutator as would ordinarily be used in any two pole motor. In order to commutate properly with any number of pairs of poles, it is necessary that the brushes malte one complete revolution around the con'nnutator for every pair of poles. In the drawings the field structure is shown provided with three pairs of poles and the brushes are so geared that they malre three revolutions around the commutator for every revolution of the field structure.

In order to stop and control the rotating field structure, I provide electrically-operated neans which, in the preferred form of my invention, comurises two brakes, one on each side of the rotating field structure so that the thrust of the braking disks Will be balanced. Each brake comprises the braking disk 28, made of magnetic material such as iron or steel, secured to the inner face of the casing 5. Each braking disk 28 is annular in form and is prevented from rotating by pins 29 secured thereto, and which are adapted to slide freely in slots drilled in the inner face of the casing 5. The sides of the field structure are faced off perfectly true so as to present a flat surface to the braking disks 28, which are faced With some suitable friction material, such as leather, Wood or fabric made for that purpose. The inner faces of the casings 5 are provided With holes which serve to hold spiral springs 30 adapted to force the braking disk 28 against the sides of the field structure and prevent it from turning. When it is desired to operate the motor, it is necessary that the braking disks 28 should not be in frictional engagement With the field structure. To accomplish this result, I preferably provide suitable circular coils 31 mounted in the casing 5, these coils 31 acting as brake magnets. The braking disks 28 being of magnetic material act as armatures for the brake magnets and When cur` rent is sent through the coils 31, the disks 28 are attracted toward the casings 5. The springs 30 are thereby compressed and the field structure is free to turn. When the current is cut off from the brake coils 31, the springs 30 Will force the braking disks 28 up against the sides of the field structure, thereby preventing its further rotation up to the amount of the braking effect.

In case the current supply should suddenly cease or be cut ofi', it is desirable that means be provided for stopping the movement of the rope 9 and coperating With the braking disks 28 to prevent further rotation of the field structure. In the preferred form of my invention, said means comprise the gripper magnet coil 32 suitably mounted Within the casing 8 secured to the frame 1, the plunger 34 adapted to move up and down Within the coil 32 and operate the toggle levers 35, 35 secured to the plunger, the gripper shoes 36, 36, one of which is mounted on the frame l, the other being secured to the movable block 37 carried by one of the toggle levers 35, and the spring 3'8 for forcing down the plunger 34 Whenever the current is cut off the gripper magnet coil 32. I also provide the screw 39 for adjusting the tension on the spring 38. Whenever the current is cut off from the gripper magnet coil 32, the spring 38 forces down the plunger 34 and the toggle action of the levers 35 forces in the movable block 37 thereby causing the shoes 36 to grip the rope 9 and hold it from moving.

IVhen electrically connected up, the motor fields and armature are connected across the line or power mains (not shown) through a rheostat (not shown) for starting, stopping or reversing the fields, and making or breaking the circuit.

It Will be obvious that numerous omissions, substitutions and changes may be made in the parts, arrangements, constructions and Wiring herein shovvn and described, Without departing from my invention.

IVhat I claim, and desire to secure by Letters Patent, is:

1. An electric motor comprising a rotatable field structure constituting a pulley, and a stationary` armature encircling said field structure.

2. In an electric motor, the combination with an adjustable rotatable field structure constituting a pulley, of a stationary armature concentrically arranged about said structure, and means for bringing said armature and structure into eccentric relation with each other.

3. The combination With an electric motor, comprising a rotatable field structure constituting a pulley, and a stationary armature encircling said field structure, of a fieXible connector driven by said field structure.

4. The combination with an electric motor, comprising a rotatable field structure, and a stationary armature encircling said field structure, of a flexible connector partly surrounding and engaging said field structure and driven thereby.

5. In an electric motor, the combination with an adjustable rotatable field structure constituting a pulley, of a stationary armature encircling said field st-ructure, a commutator for said armature, and means for controlling the rotation of said field structure.

6. In an electric motor, the combination with a stationary armature, of a commutator therefor, and a rotatable field structure, said field structure comprising a plurality of poles, the outer ends of said poles being connected together so as to form a continuous circular ring.

7. In an electric motor, the combination with a stationary armature, of a commutator therefor, and a rotatable eld structure, said field structure comprising a plurality of poles provided With pole-pieces and connect-- ing pieces of non-magnetic material therebetween to form a continuous ring.

8. In an electric motor, the combination With a stationary armature, of a. commutator therefor, and a rotatable field structure, said field structure comprising a plurality of poles provided With pole-pieces and connecting pieces of non-magnetic material therebetween to form a continuous ring, the peripheral surface of said ring being provided with grooves to accommodate a driving rope.

9. ln an electric motor, the combination with an adjustable field structure constituting a pulley, of a stationary armature encircling said structure, and means for bringing said armature and the field of said structure into closer magnetic relation at any point.

10. n an electric motor, the combination with an adjustable field structure constituting a pulley and comprising a field magnet, of a stationary armature encircling said structure, and means for lessening the airgap between said armature and field at any predetermined point.

ll. ln an electric motor, the combination with a rotatable field structure, its peripheral surface having' grooves to receive a driving rope, of a. stationary armature encircling said field structure, and a commutator for said armature.

12. ln an electric motor, 'he combination with a rotatable field structure adapted to be used as a sheave to operate a flexible driving connector, of a stationary armature encircling said field structure, said armature being provided with slots to allow the passage of said connector therethrough.

18. ln an electric motor, the combination with a frame, of a. field structure rotatably mounted therein, the peripheral surface of said field structure being provided with grooves to accommodate a driving rope, and an armature mounted in said frame and encircling said field structure, said armature being provided with slots to allow the passage of said rope therethrough.

lll. ln an electric motor, the combination with a frame, of a held structure rotatably mounted therein, the peripheral surface of said field structure being provided with grooves to receive a diving rope, an armature mounted in said frame and encircling said field structure, said armature having slots to allow the passage of said rope therethrough, a stationary commutator, rotatable brushes bea ing upon said commutator, and operating means connecting said rotatable field structure with said brushes.

l5. lfn an electric motor, the combination with an adjustable rotatable field structure adapted to be used as a pulley to operate a flexible driving connector, of a stationary armature concentrically arranged about said field structure and provided with slots to allow the passage of said connector therethrough, and means for bringing said field structure and armature into eccentric relation with each other.

1G. ln an electric motor, the combination with an adjustable rotatable field structure adapted to be used as a pulley to operate a flexible driving connector of magnetic material, of a stationary armature concentrically arranged about said field structure and provided with slots to allow the passage of said connector therethrough, and means for bringing a pre-determined portion of said field structure into closer magnetic relation with said armature to increase the magnetic attraction upon said connector.

17. The combination with an electric niotor, comprising a rotatable field structure provided with grooves to accommodate a driving rope, a stationary armature eiicircling said field structure and provided with slots to allow the passage of' said rope therethrough, and a coiiiiiiutator for said arma* ture, of means for gripping said rope upon failure of the current supplied to said motor.

18. rlhe combination with an electric inotor, comprising a rotatable field structure adapted to be used as a pulley to operate a flexible driving connector, a stationary armature encircling said field structure and provided with slots to allow the passage of said connector therethrough, and a' commutator for said armature, of electrically-operated means for controlling the rotation ot' said field structure, and electrically-operated means for gripping said connector upon the failure of the current supplied to said motor.

19. The combination with an electric motor, comprising a rotor adapted to drive a flexible connector, and a stator ar anged about said rotor, of a flexible connector of magnetic material interposed between said rotor and stator and driven by said rotor.

20. The combination with an electric motor, comprising a rotatable field structure adapted to drive a flexible connector, and a stationary armature arranged about said field structure,of a flexible connectorof niagnctic material interposed between said field structure and armature and engaging said field structure.

2l, The combination with an electric motor, comprising a rotatable field structure adapted to driie a flexible connector, a stationary armature arranged aboutl said field structure and having slots for the passage of said connector therethrough, and a cominutator for said armature, of a flexible connector' of magnetic material interposed -between said field structure and armature and driven by said field structure.

2Q. rlhe combination with an electric inotor, comprising a rotatable field structure adapted to drive a flexible connector, a stationary arinature arranged about said field structure and having slots for the passage of said connecter therethrough, and a commutator for said armature, of a flexible con nector of magnetic material adapted to engage and partly surround said field structure so that a portion of the magnetic linesl of force between said field structure and armature will pass through said connector.

23. The combination with an electric inotor, comprising a rotatable field structure and a stationary armature encircling said structure, of a flexible connector adapted to engage and be driven by said field structure, and means for controlling the rotation of said field structure upon failure of the current supplied to the motor.

24. The combination with an electric motor, comprising an adjustable rotor adapted to be used as a pulley, and a stator arranged about said rotor, of a flexible connector of magnetic material adapted to be driven by said rotor, and means for varying the number of magnetic lines of force between said rotor and stator passing through said connector.

25. The combination with an electric motor, comprising an adjustable field structure adapted to be used as a pulley, a stationary armature encircling said field structure, and a commutator therefor, of a fieXible connector of magnetic material adapted to be driven by said field structure, and means for varying the number of magnetic lines of force passing through said connector between said field structure and armature.

26. The combination with an electric motor, comprising a frame, a field rotatably mounted therein, the peripheral surface of said field being provided with grooves to receive a driving rope, a stationary armature mounted. in said frame and encircling said field, said armature being slotted to allow the passage of said rope therethrough, a stationary commutator, rotatable brushes bearing upon said commutator, and operating means connecting said rotatable field with said brushes, of means for automatically controlling the rotation of said field, and means for automatically gripping said rope upon failure of the current supplied to said motor.

27. The combination with an electric motor, comprising a rotatable field structure adapted to drive a flexible connector, and a stationary armature arranged about said field structure, of a fiexible connector interposed between said field structure and armature and driven by said field structure, and means for gripping said connector upon failure of the current supplied to the motor.

In testimony whereof, I sign this specification in the presence of two witnesses.

ETHELBERT M. FRASER.

Witnesses:

WV. C. MARGEsoN, L. F. LITTLE.

Copies ot this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

